Device for closing the pouring hole of a receptacle for liquid metal

ABSTRACT

A fixed plate member, and a movable plate member is mounted against the fixed plate member. The fixed plate member consists of a fixed metal support plate having a plane outer metal surface and a cutout in which is accommodated a wear part made of refractory material which is pierced with at least one pouring orifice. The lower refractory surface of the refractory wear part is flush with the plane outer metal surface of the fixed metal support plate. The major portion of the rubbing surface of the fixed plate member and contact with the movable plate member consists of only the plane outer metal surface, while only the remaining minor portion consists of the lower refractory surface of the wear part. The fixed metal support plate contains a cooling chamber for holding cooling fluid which circulates to the plane outer metal surface of the fixed metal support plate via an orifice formed in the fixed metal support plate which also has a groove communicating with the cooling chamber and running along a circumference of the cutout in order to circulate the cooling fluid to cool the wear part.

BACKGROUND OF THE INVENTION

The present invention relates to a device for closing the pouring holeof a steel-making or metallurgical receptacle such as a pouring ladle,ingot mould or continuous-casting distributor, and more particularly toa device with a moveable plate.

A conventional pouring-hole closing device is composed essentially of aplate made of refractory material which is accommodated in a metalcasing fixed under the bottom of the receptacle and of a moveable plate,likewise made of refractory material, which is mounted against the fixedplate so that it can be displaced by a translational or rotationalmovement in order to close the pouring orifice of the fixed plate or toposition a pouring orifice with which it is provided opposite thepouring orifice of the fixed plate.

When the liquid metal is poured, the stream of metal flows out throughthe pouring channel of the internal nozzle, made of refractory material,of the receptacle and passes through the pouring orifices in theelements, made of refractory material, of the fixed plate and of themoveable plate of the closing device. The molten metal erodes the wallof the pouring channel and causes fairly rapid wear of the wall of thepouring orifices in the refractory elements of the fixed and moveableplates owing to the high temperature of the liquid metal. In addition,owing to the temperature a decarburisation of the binder used in themanufacture of the refractory plates occurs, which leads to adeterioration of the rubbing surfaces of the two plates, whichdeterioration hinders the sliding of the moveable refractory plateagainst the fixed refractory plate during each pouring operation.

The wear of the refractory material around the pouring orifice and thedeterioration of the rubbing surfaces makes it necessary to replace therefractory plates fairly regularly after a certain number of pouringoperations. These replacements are obviously costly in terms ofrefractory material.

SUMMARY OF THE INVENTION

The object of the present invention is, on the one hand, to make thesereplacements less expensive and, on the other hand, to improve thesliding of the moveable plate against the fixed part.

This objective is achieved, in accordance with the invention, by meansof a device for closing the pouring hole of a steel-making ormetallurgical receptacle, which device is distinguished in that thefixed plate consists of a metal support plate having a plane outersurface and exhibiting a cutout in which is accommodated a wear partmade of refractory material which is pierced with at least one pouringorifice, the lower face of the wear part being flush with the planeouter surface of the support plate, so that the rubbing surface of thefixed plate in contact with a moveable plate consists of a metal surfacefor the most part and of a refractory surface of limited extent.

In a particular embodiment, the wear part has a rim cooperating with acorresponding rim provided on the wall of the cutout.

By virtue of the invention, it is sufficient to replace the wear partalone after a certain number of pouring operations while retaining themetal support plate, which is considerably more convenient, quicker andless costly than if the entire fixed plate has to be replaced, as is thecase with the conventional closing devices. The same metal support platecan thus be used for a large number of pouring operations with thesimple replacement of the wear part.

Advantageously, the support plate has a cooling chamber on its innerface. In addition, the metal support plate may have a groove runningalong the circumference of the cutout in order to circulate a coolingfluid.

The moveable plate of the closing device according to the inventionconsists of a metal support plate pierced with at least one cutout inwhich is accommodated a wear part made of refractory material, throughwhich at least one pouring orifice passes.

By virtue of the fact that the rubbing surface of the wear part of themoveable plate slides against a fixed surface which is for the most partmetal, the sliding is performed more easily and with less wear of thesurface of the moveable refractory wear part. And the cooling of themetal support plate and the wear part of the fixed plate further adds tothe lessening of the deterioration of the refractory surfaces and to theimprovement of the sliding of the moveable plate against the fixed platein accordance with the invention.

Other aspects of the invention will become apparent on reading thedescription which follows, in which the invention is explained ingreater detail with the aid of the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an exemplary embodiment of the deviceaccording to the invention, mounted under an ingot mould;

FIG. 2 shows, in particular, the fixed plate represented in FIG. 1;

FIG. 3 is an exploded view, in section, of the fixed and moveable platesrepresented in FIG. 1;

FIG. 4 is a plan view of the fixed plate shown in FIG. 2;

FIGS. 5 and 6 are plan views of the parts constituting the fixed plateshown in FIG. 2;

FIGS. 7 and 8 illustrate two exemplary alternative embodiments of thefixed plate in accordance with the invention;

FIG. 9 is a top view of the moveable plate shown in FIG. 1;

FIG. 10 is a view in section along the line X--X of FIG. 9; and

FIG. 11 illustrates an exemplary alternative embodiment of the moveableplate shown in FIG. 10.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to FIG. 1, an exemplary embodiment of a pouring-holeclosing device according to the invention can be seen. This device ismounted under the bottom 1 of an ingot mould having a pouring hole 2delimited, as is known per se, by an internal nozzle 3 made ofrefractory material, constructed in the refractory lining 4 of theingot-mould bottom. The device for closing the pouring hole comprises afixed plate which is fixed under the ingot mould and a moveable platewhich is mounted so as to be able to slide against the fixed plate underthe action of a drive mechanism (not shown), known per se.

The fixed plate is described first of all with the aid of FIGS. 2 to 6.Fixed under the ingot mould is a metal mounting casing 5 (seen partiallyin FIG. 1), in which is mounted a metal support plate 11, made ofstainless steel with a polished surface, having a plane horizontal outerface 10A. In the example illustrated, the metal part 11 is formed with avertical peripheral rim 12 projecting from its inner face. Formed in thesupport plate 11 is a cutout 13, in which is fitted a part 14 made ofrefractory material through which passes a cylindrical orifice 15 whichis placed in alignment with the pouring hole 2 of the ingot mould orother metallurgical or steel-making receptacle. The upper face of therefractory part 14 is intended to be constructed under the calibrationwasher, which is provided at the end of the internal nozzle. The parts11 and 14 may be of any form in plan. The inner horizontal profile ofthe cutout 13 and the outer horizontal profile of the part 14 arepreferably chosen so as to prevent the movement of the refractory part14 in its housing. FIGS. 4, 5 and 6 illustrate an exemplary profile ofthe parts 11 and 14.

On the circumference of the refractory part 14 there is provided a rim16 which is intended to cooperate with a corresponding rim 17expediently formed on the side wall of the cutout 13. The refractorypart 14 has an outer face 10B which is flush with the outer surface 10Aof the metal support plate 11, with a small surface compared to thetotal surface which serves as rubbing surface in contact with themoveable plate, which rubbing surface is for the most part metal.

Since it is the refractory part 14 in which is formed the pouringorifice which is eroded as the number of pouring operations increases,it is sufficient to replace this part 14 alone, which is considerablymore convenient, quicker and less expensive than if the entire plate 11has to be replaced, as is the case in the conventional constructions.The same metal support plate 11 can thus be used for a large number ofpouring operations with the simple replacement of the refractory part 14or wear part, which represents a considerable saving in investmentcosts.

In the exemplary embodiment illustrated in FIGS. 1 to 3, the refractorypart 14 has a skirt 18 which projects from the top of the part so as tobe accommodated in a recess provided in the calibration washer of theinternal nozzle 3. This prevents the destruction of this washer duringthe replacement of the refractory wear part 14. In contrast, in theknown constructions the calibration washer generally has a projectingflange on which the conventional refractory plate fits, and thisprojecting flange is frequently destroyed during the replacement of therefractory plate.

In the preferred embodiment illustrated, the metal support plate 11 isadvantageously formed with rims 12 so as to create on the inner face acooling chamber 30. The latter communicates with a groove 31 which runsalong the circumference of the cutout 13 and hence along thecircumference of the refractory part 14 in order to circulate a coolingfluid, for example air. The cooling fluid may, for example, be injectedvia a conduit 32 connected to a fluid-supply source and the coolingfluid may be evacuated via an evacuation orifice such as, for example,33. In this way, the refractory part 14 is cooled during the moltenmetal pouring operations, thus reducing the deterioration of therefractory material owing to the high temperature. At the same time, thelowering of the temperature of the support plate 11 and of therefractory part 14 also brings about a reduction of the temperature ofthe moveable plate adjoining them. The orifice 19 formed in the supportplate 11 expediently permits the passage of cooling fluid to the outerface 10A of the support plate 11, that is to say permits the coolingfluid to be brought to the rubbing surface in contact with the moveableplate, thus improving the sliding of the moveable plate against thefixed plate 11-14. Discharge channels 34 may advantageously be providedin the lateral rim 12 of the support plate (FIG. 4 shows three of themby way of example) for the removal of refractory material dust, which isdetached from the moveable plate during the rubbing thereof against thefixed plate.

The metal support plate 11 and the refractory part 14 may, of course,have various embodiments. FIGS. 1 and 2 show, by way of example, anembodiment in which the refractory part has a projecting skirt 18. FIGS.7 and 8 represent two other exemplary embodiments in which therefractory part 14 has no projection on its upper face. Furthermore, inthese two alternative embodiments, the outer face of the metal supportplate 11 has a groove 35 in communication with a cavity 36 to facilitatethe circulation of air around the rubbing surfaces and to reduce themetal rubbing surface. The embodiment of FIG. 8 differs again from thatof FIG. 7 in that the peripheral rim of the refractory part 14 isinverted. In the example of FIG. 7, the refractory part 14 is placed onthe side of the inner face of the support plate 11. The replacement ofthe refractory wear part 14 requires the removal of the metal supportplate 11, it being necessary for these two parts to be mounted togetherin the mounting casing fixed under the receptacle. With the embodimentof FIG. 8, on the other hand, the refractory wear part 14 can bereplaced without removing the metal support plate 11.

The moveable plate of the device for closing the pouring hole may alsobe constructed, in accordance with the invention, with a wear part. Anexemplary embodiment is illustrated in FIGS. 9 and 10, FIG. 9 being atop view and FIG. 10 being a sectional view. The moveable platecomprises a metal support plate, made of stainless steel with a polishedsurface for example, having at least one cutout 23 in which is fitted apart 24 made of refractory material, through which a pouring orifice 25passes. In the embodiment illustrated, the refractory part 24 is formedwith two pouring orifices 25, but the number of orifices could be otherthan two. The refractory part 24 rests on rims formed inside a verticalperipheral rim 22 provided on the upper face of the metal support plate21.

The upper face 20 of the refractory part 24 extends slightly beyond theedge of the peripheral rim 22. This face constitutes the rubbing facebearing against the rubbing face 10 of the fixed plate when the metalsupport plate 21 is mounted in its mounting casing 6 (see FIG. 1)coupled to a drive mechanism, known per se. When the moveable plate21-24 is thus put into place on a steel-making or metallurgicalreceptacle, one pouring orifice 25 is in alignment with the pouringorifice 15 of the fixed plate and with the pouring hole 2 of thereceptacle. The other pouring orifice or the other pouring orificesserve as standby reserve orifices, ready to be placed in the operatingposition under the pouring hole 2 by sliding, with a translational orrotational movement, the moveable plate against the fixed plate. Thecollars 27 which surround the pouring orifices 25 on the outer face ofthe moveable plate serve for the connection of an external nozzle (notshown).

In the same way as the construction of the fixed plate in accordancewith the invention, in which the part made of refractory material islimited to the wear part surrounding the pouring orifice, theconstruction of the moveable plate as explained hereinabove has theadvantage of helping to make the replacement of the worn refractoryelements considerably less expensive than in the conventionalconstructions. It should also be noted that the wear of the rubbingsurface of the refractory part 24 is less than in the conventionalconstructions, since this surface rubs here, for the most part, againsta metal surface 10A. In addition, this facilitates the sliding of thehot parts against one another. To facilitate the installation of therefractory wear part 24 in the cutouts 23 and also to facilitate theremoval of this wear part, the flanks of the cutouts 23 may expedientlybe oblique, as illustrated in FIG. 11.

It is understood that the embodiments of the invention described in thetext above are examples given by way of illustration and the inventionis in no way limited to these examples. Any modification, any variationand any equivalent arrangement must be considered to be within the scopeof the invention.

I claim:
 1. In a device for closing the pouring hole of a steel-makingor metallurgical receptacle, said device comprising a fixed plate membermounted under the pouring hole of a receptacle and a movable platemember mounted against the fixed plate member so that the movable platemember can be displaced relative to the fixed plate member, therebypresenting a rubbing surface of the movable plate member against arubbing surface of the fixed plate member, the improvement wherein:thefixed plate member comprises a fixed metal support plate (11) having aplane outer metal surface (10A) and a cutout (13) in which isaccommodated a wear part (14) made of refractory material which ispierced with at least one pouring orifice (15); a lower refractorysurface (10B) of the refractory wear part (14) is flush with the planeouter metal surface (10A) of the fixed metal support plate (11); a majorportion of said rubbing surfaces of the fixed plate member in contactwith the movable plate member consists of the plane outer metal surface(10A), and only a remaining minor portion consists of the refractorysurface (10B); the fixed metal support plate (11) has on an inner facethereof a cooling chamber (30) which is adapted to hold cooling fluidand which communicates with the plane outer metal surface (10A) of thefixed metal support plate (11) via an orifice (19) formed in the fixedmetal support plate (11); and the fixed metal support plate (11) has agroove (31) communicating with said cooling chamber (30) and runningalong a circumference of the cutout (13) in order to circulate a coolingfluid for cooling the wear part (14).
 2. Device according to claim 1,wherein the wear part (14) has a rim (16) cooperating with acorresponding rim (17) on the wall of the cutout.
 3. Device according toclaim 1, wherein the fixed metal support plate (11) has a lateral rim(12) containing at least one discharge channel (34) for dust.
 4. Deviceaccording to claim 1, wherein the wear part (14) has a shirt (18)projecting from an upper face of the wear part around the pouring office(15).
 5. Device according to claim 1, wherein the fixed metal supportplate (11) is mounted in a metal mounting casing (5) fixed to thesteel-making or metallurgical receptacle.
 6. Device according to claim1, wherein the movable plate member comprises a second metal supportplate (21) pierced with at least one cutout (23) in which isaccommodated another wear part (24) made of refractory material andthrough which said at least one pouring orifice (25) passes.
 7. Deviceaccording to claim 6, wherein the second metal support plate (21) isaccommodated in a metal mounting casing (6) coupled to a drive mechanismto displace the second metal support plate (21) relative to the fixedmetal support plate (11) of the fixed plate member.